Nanoliposomal VEGF-R2 peptide vaccine acts as an effective therapeutic vaccine in a murine B16F10 model of melanoma.

Background: The vascular endothelial growth factor receptor-2 (VEGFR-2) plays an important role in melanoma development and progression. Peptide vaccines have shown great potential in cancer immunotherapy by targeting VEGFR-2 as a tumor-associated antigen and boosting the immune response against both tumor cells and tumor endothelial cells. Despite this, the low efficiency of peptide vaccines has resulted in moderate therapeutic results in the majority of studies. Enhancing the delivery of peptide vaccines using nanoliposomes is an important strategy for improving the efficacy of peptide vaccines. In this regard, we designed VEGFR-2-derived peptides restricted to both mouse MHC I and human HLA-A*02:01 using immunoinformatic tools and selected three peptides representing the highest binding affinities. The peptides were encapsulated in nanoliposomal formulations using the film method plus bath sonication and characterized for their colloidal properties. Results: The mean diameter of peptide-encapsulated liposomes was around 135 nm, zeta potential of - 17 mV, and encapsulation efficiency of approximately 70%. Then, vaccine formulations were injected subcutaneously in mice bearing B16F10-established melanoma tumors and their efficiency in triggering immunological, and anti-tumor responses was evaluated. Our results represented that one of our designed VEGFR-2 peptide nanoliposomal formulations (Lip-V1) substantially activated CD4+ (p < 0.0001) and CD8+ (P < 0.001) T cell responses and significantly boosted the production of IFN-γ (P < 0.0001) and IL-4 (P < 0.0001). Furthermore, this formulation led to a significant decrease in tumor volume (P < 0.0001) and enhanced survival (P < 0.05) in mice. Conclusion: Our findings suggest that the nanoliposomal formulation containing VEGFR-2 peptides could be a promising therapeutic vaccination approach capable of eliciting strong antigen-specific immunologic and anti-tumor responses. Supplementary Information: The online version contains supplementary material available at 10.1186/s12645-023-00213-7.

Application of VEGF/VEGFR peptide vaccines in cancer: A systematic review of clinical trials.

Peptide vaccines that target vascular endothelial growth factor (VEGF) pathway have shown promising results in inducing strong anti-tumor immune responses with minimal toxicity in various clinical studies. This systematic review was conducted to provide a comprehensive evaluation of the therapeutic efficacy, immune response, survival rate, and side effects of VEGF/VEGF receptor-based peptide vaccines. VEGF/VEGFR2 peptide vaccines were found to be safe and effective in inducing anti-tumor immune responses, while induced moderate clinical benefit. In this regard, further clinical trials are necessary to fully evaluate their clinical effects and the exact correlation between induction of immune response and clinical outcomes.

Tim-3 and PD-1 blocking cannot restore the functional properties of natural killer cells in early clinical stages of chronic lymphocytic leukemia: An in vitro study.

Background: Programmed death-1 (PD-1) and T-cell immunoglobulin- and mucin-domain-containing molecule-3 (Tim-3) are two major immune checkpoint receptors expressed on immune cells and their expression is related to the exhaustion phenotype. In the present in vitro study, blocking of PD-1 and Tim-3 molecules was performed on isolated natural killer (NK) cells from patients with chronic lymphocytic leukemia (CLL) to restore their functional properties. Materials and Methods: NK cells fraction was positively isolated from fresh peripheral blood of 18 CLL patients, treated with anti-PD-1 and anti-Tim-3 blocking monoclonal antibodies and co-cultured with K562 target cells to evaluate their apoptosis induction by Annexin V-PI method. Blocked NK cells were also incubated with anti-CD107a antibody to assess their degranulation properties by flow cytometry. The level of secreted tumor node factor-alpha (TNF-α) and interferon-gamma (IFN-γ) by NK cells was also measured by ELISA. Results: Our results showed similar functional properties in terms of degranulation and apoptosis of K562 target cells by isolated NK cells from CLL patients in PD-1/Tim-3 blocked and control groups. It was also shown that blocking of PD-1 and Tim-3 could not improve the production of pro-inflammatory TNF-α and IFN-γ cytokines by isolated NK cells from CLL patients. Conclusion: Altogether, our results indicated that pretreatment of NK cells with anti-PD-1 and anti-Tim-3 blocking antibodies in CLL patients at early clinical stages cannot improve their functional properties. Besides many other malignancies, the application of checkpoint inhibitors in CLL needs more investigations and complementary studies.

COVID-19 in children with inborn errors of immunity: clinical scenarios.

The new emerging virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causes a huge burden of morbidity and mortality worldwide. One of the predisposing factors which might increase the infection susceptibility and its complications can be the Inborn Errors of Immunity (IEI). One hundred and seventeen primary immunodeficient (PID) pediatric patients were monitored from March to December 2020 for any signs and symptoms of SARS-CoV-2 infection. Among them twenty-eight children were symptomatic and nineteen out of the twenty-eight patients took the coronavirus PCR test. Out of them, the PCR test results of 9 patients were positive. Herein, we report the nine cases of pediatric patients with IEI who were also infected with SARS-CoV-2 with a positive PCR test. We observed a variation in clinical manifestations, clinical courses, and outcomes among IEI pediatric patients affected with COVID-19. In our survey, prompt diagnosis and appropriate monitoring for possible complications were shown to be effective in reducing the mortality rate of the SARS-CoV-2 affected patients with IEI. Although there is no approved treatment for SARS-CoV-2 infection, supportive treatment might reduce the complications and lead to better outcomes. This study received approval from the Research Ethics Committee of Mashhad University of Medical Science with the ethics code of IR.MUMS.REC.1399.155. (https://ethics.research.ac.ir/EthicsProposalViewEn.php?id=129963).

Blockade of PD-1 and TIM-3 immune checkpoints fails to restore the function of exhausted CD8+ T cells in early clinical stages of chronic lymphocytic leukemia.

Blocking antibodies targeting immune checkpoint molecules achieved invaluable success in tumor therapy and amazing clinical responses in a variety of cancers. Although common treatment protocols have improved overall survival in patients with chronic lymphocytic leukemia (CLL), they continue to relapse and progress. In the present in vitro study, the application of anti-PD-1 and anti-TIM-3 blocking antibodies was studied to restore the function of exhausted CD8+ T cells in CLL. CD8+ T cells were isolated from peripheral blood of 20 patients with CLL, treated with blocking antibodies, and cocultured with mitomycin-frozen non-CD8+ T cell fraction as target cells. Cultures were stimulated with anti-CD3/CD28 antibodies to assess the proliferation of CD8+ T cells by MTT and stimulated with PMA/ionomycin to measure the levels of CD107a expression and cytokine production by flow cytometry and ELISA, respectively. Our results showed that the blockade of PD-1 and TIM-3 does not improve the proliferation of CD8+ T cells in CLL patients. No significant difference was found between control and blocked groups in terms of degranulation properties and production of IFN-γ, TNF-α, IL-2, and IL-10 by CD8+ T cells. We observed that pre-treatment of CD8+ T cells with blocking antibodies in CLL patients at early clinical stages had no effects on restoring their functional properties. Further in vitro and in vivo complementary studies are required to more explore the utility of checkpoint inhibitors for CLL patients.